The present invention relates to a turbine helper drive apparatus wherein an AC motor is coupled to a turbine, and a torque generated by the AC motor is added to a torque generated by the turbine, thereby driving a load.
A large compressor, for example, is often driven at a constant speed by a steam turbine. When the capacity of the compressor is increased, the turbine and its associated facilities must be exchanged.
Recently, since the rate of electric power is cheaper after midnight, it is more economical, in the nighttime, for operation to use a motor than a steam turbine.
Therefore, a demand has arisen to couple a motor to the turbine so as to use it as a helper. However, an appropriate drive method for this has not yet been provided.